Hyopsodus sp.

Bai, Bin, Wang, Yuan-Qing, Zhang, Xin-Yue & Meng, Jin, 2021, A new species of the “ condylarth ” Hyopsodus from the middle Eocene of the Erlian Basin, Inner Mongolia, China, and its biostratigraphic implications, Acta Palaeontologica Polonica 66 (4), pp. 767-777 : 770

Hyopsodus sp.

Fig. 1B .

Material.— IVPP V 28283 , a left mandible with a heavily worn m2 and roots of m3 from the upper level of the lower part of the Arshanto Formation (AS-2), Huheboerhe, Erlian Basin, Inner Mongolia, China .

Description.—The m2 is about 11% smaller than that of Hyopsodus arshantensis sp. nov. (IVPP V 28282) in longitudinal dimensions ( Table 1). It differs from H. arshantensis sp. nov. in having a more lingually extended paralophid, and the angle between the cristid obliqua and the posthypocristid is slightly less than 90°. Only the roots of m3 are preserved on the specimen. The m3 was almost as long as m2, but it appears to have been narrower than the latter. The cross section of the anterior root is an anteroposteriorly compressed oval, and that of the posterior one is an elongated ellipsoid.

Figures

Fig. 1. The middle Eocene “condylarth” mammal Hyopsodus arshantensis sp. nov. (A) and Hyopsodus sp. (B) from the Arshanto Formation of the Erlian Basin, Inner Mongolia, China. A. IVPP V 28282 from Chaganboerhe, m1–m2 in occlusal (A1), buccal (A2), and lingual (A3) views; mandible in buccal view (A4). B. IVPP V 28283 from Huheboerhe, mandible in buccal view (B1); m2 and m3 root in occlusal (B2), buccal (B3), and lingual (B4) views.